Project on Concrete Mix Design for various grades of Concrete
The Concrete Mix Design for M35 grade concrete with fly ash -
- Propotoning :
- Grade :M35
- Cement type:OPC 43 grade(IS8112)
- Mineral admixture:Fly ash
- Maximum nominal size of aggregate:20mm
- Maximum cement content:320kg/m^3(Table :5 IS 456-2000,based on exposure condition)
- Maximum w/c ratio :0.45(table 5,IS 456-2000)
- Workability:100mm
- Exposure condition:Severe
- Type of aggregate ;Crussed angular aggregate
- Maximum cement content=450kg/m^3
- Chemical admixture: superplasticizer IS 9103
- Data for testing:
- Cement :OPC 43 grade(IS8112)
- Specific gravity of cement:3.15
- Specific gravity of fly ash:2.2
- Chemical admixture: superplasticizer IS 9103
- Specific gravity of coarse and fine aggregate:2.74
- Water absorption:
- coarse aggregate:0.5%
- Fine aggregate:1%
- Fine surface moisture of fine and coarce aggregate: Nil
- Target mean strength:
F'ck=35+1.65*5=43.25
- Water cement ratio:
W/C ratio=0,45(Table 5 IS 456 2000)
- Water content calculation:
Max water content for 20mm aggregate+186 ly (Table 2 IS 1026:2009)for 25mm to 50mm slump range
for 100mm slump=186+(6/100)*186
=197 lt
as siperplastisizer is used the water content reduces to 30%
Based on trail water content reduction of 29% is achieved with plastisizer
Hence arrived water content+197*0.71=140 lt
- Calculation of cement content:
w/c ratio=0.4
c=w/0.4=140/0.4
c=350kg
so,
w/c ratio=140/385=0.364
Fly ash at 30% total cementatious material content = 35-30 % =115kg
Cement (OPC)=385-115=270kg
Saving of cement while using flyash=350-270=80kg
Flyash beimg utilized=115kg
Volume of corse aggregate=0.64*0.9=0.576
Volume of fine aggregate=1-0.576=0.424
Mix calculations:
Mix calculation per unit volumeof concrete:
a. Volume of concrete=1m^3
b. Volume of cement =(Mass of cement/Specific gravity of cemment)*1/100
=(270/3.15)*1/100
=0.086m^3
c. Volume of fly ash +(115/2.2)*1/1000
=0.052m^3
d. Volume of water=(140/1)*1/1000=0.140m^3
e. Volume of chemical admixture=(7.6/1.14)*1/1000=0.006m^3
f.Volume of aggregate=a-(b=c=d=e)
=1-(0.86+0.052+0.140+0.006)=0.716 m^3
g. Mass of coarse aggregate =0.716*0.424*2.74*1000=1130kg
h. Mass of fine aggregate=0,716*0.424*2.74*1000=831kg
MIX RATIO:
1:2.15:2.94
The Concrete Mix Design for M50 grade concrete -
F'ck=Fck+(1.65*s)
F'ck=50+(1.65*5)
F'ck=58.25N/mm^2
F'ck:Tagret mean strength at 28 days
Fck:Characterstic compressive strength at 28 days
s:Standard daviation (Table 8, Page number 23,IS 456)
STEP:1
W/C ratio =0.45(Table no 5 for different exposure conditions,Clause 8.2.4.1(IS 456-2000))
Based on experience w/c ratio =0.4
STEP:2
Selection of water content:From table-2 from IS 10262:2009
The maximum water content for slump 20mm to 50mm=186kg=186L
for 100mm slump=186+(6/100)*186=197ly
Based on trail water reduction of 29%
Hence water content=197*0.71=140lt
STEP:3
Selection of cement content :
It can be calculate by W/C ratio
Water content(W)=186kg
Water cement ratio(W/C)=0.4
Cement content(C)=W/0.4
=140/0.4
=350kg
STEP:4
Volume of coarse=0.64*0.9=0.576
and fine aggregate=1-0.576=0.424
content:Determined from Table-3 IS 10262:2009
STEP:5
Mix calculation
The mix calculation per unit volume shall be as follows:
a)Volume of concrete=1m^3
b)Volume of cement=Mass of cement/Specific gravity of cement *1/1000
=(350/3.15)*1/100-=0.111m^3
c)Volume of water= Mass of water/Specific gravity of water*1/1000
=(140/1)*1/1000=0.140m^3
d)Volume of chemical admixtures=Mass of chemical admixtures/Specific gravity of admixtures*1/1000
(7.6/1.145)*1/1000=0.006m^3
e)Volume of aggregate(FA&CA)=(a-(b+c+d))
=1-(0.11+0.140+0.006)=0.743m^3
f)Mass of coarse aggregate=e*Volume of CA*Specific gravity of CA*1000
=0.743*0.576*2.74*1000=1173kg/m^3
g)Mass of fine aggregate=e*Volume of FA*Specific gravity of FA*1000
=0,743*0.424*2.74*1000=863kg/m^3
STEP:6
Mix propotion:
Cement =( 350)kg/m^3
Water =( 140)kg/m^3
Fine aggregate=(863 )kg/m^3
Coarse aggregate =(1173)kg/m^3
Chemical admixture=( 7)kg/m^3
W/C ratio=0.4
STEP:7
Mix ratio:
Cement:Fine aggregate:Coarse aggregate=1:2.46:3.35